Let D be the diameter of the Earth, F - the northern latitude angle of the Pyramid and c - the speed of light, and n = 299 792 458 a number.
F can be expressed in radians, or degrees. F in our case = n * 10
-7 degrees. Therefore the distance from the pyramid to the Ecuator is
d = F/360 * pi*D = n * 10
-7/360 * pi*D.
Now we have d -independent of any unit system, it is just relative to F and D. What we have to do now is to get rid of the m/s from the speed of light.
Here we go, since 1m = 10
-7 *(the distance from the north pole to the ecuator) then 1m = 10
-7* pi*D/4 ; and since 1day has 24 hours, each having 60 minutes, each having 60 seconds, then 1s = 1day/86400.
Now we express c = n * 10
-7 * pi*D/4 * 86400 / day (the distance travelled by light in a day)
As you can see, d and c are in a very close form:
d = n * 10-7/360 * pi*D
c = n * 10-7 * pi*D/4 * 86400 / day
Now 7777777 * d = n * 10
-7 * pi*D *
21604.936(1) and c = n * 10
-7 * pi*D *
21600 / day
Neat isn't it, D can be any number(the same for n) and 7777777 is the number that 'works' for the time interval of a day. But I said it's a theory only, because there's a difference of 4.936(1), yet that's very small compared to 21600 and could yield from the fact that there aren't exactly 10
7 meters in that distance, a day doesn't have exactly 86400 seconds, etc. and maybe those who built the pyramids knew these numbers more exactly than us, thus 7 times 7 could be the number. I wish I was as good at astronomy as I am at physics, but eh, little spare time

I'm sure astronomy plays an important role in the positioning of the pyramid. You are free to do calculations and come with other theories.